ASP.NET MVC 4 breaks ASP.NET MVC 3 projects

Question

After installing the ASP.NET MVC 4 Developer Preview, I can no longer open MVC 3 projects, with the following error message:

The project type is not supporte         


        

Answer 1

"" If you want to update your projects to MVC4, and open them as such in the visual studio, then ""

The solution is to change the projectType guids from

{E53F8FEA-EAE0-44A6-8774-FFD645390401}

to

{E3E379DF-F4C6-4180-9B81-6769533ABE47}

in the csproj file, after you install the mvc4 visual studio package.